JP5501899B2 - Substrate support plate and temporary wafer fixing method to substrate support plate - Google Patents

Description

  The present invention relates to a substrate support plate to which wear is fixed and a method for temporarily fixing a wear substrate to the substrate support plate, which are used during a manufacturing process.

  In recent years, power semiconductor devices (hereinafter referred to as “wafers”) using semiconductor wafers (hereinafter referred to as “wafers”) such as Si (silicon) wafers and SiC (silicon carbide) wafers are designed to improve power loss as follows. Such a manufacturing process is generally performed. For example, after forming a semiconductor element in the wafer surface manufacturing process, the wafer thickness is ground (or processed thinly by wet etching), and further, an insulating film or a metal is formed on the wafer back surface or wafer surface.

  In recent years, the thickness of the wafer has been extremely reduced to 100 μm or less, and the wafer is greatly warped by the weight of the wafer itself. Further, the warpage of the wafer increases due to stress caused by an insulating film, a metal film, or the like formed on the wafer front surface and the wafer back surface.

  When the warpage of the wafer becomes large, it becomes difficult to carry the wafer in the semiconductor manufacturing apparatus, so it is necessary to prevent the warpage of the wafer. Therefore, a substrate support method is provided in which a substrate such as glass or silicon (hereinafter referred to as a substrate support plate) is prepared, a wafer is attached to the substrate support plate, and a predetermined manufacturing process is performed on the attached wafer. Is generally adopted.

  Here, when a wafer is attached to the substrate support plate, the overlapping amount of the substrate support plate and the wafer needs to be within a desired range. That is, in plan view, the wafer is contained in the substrate support plate, and the deviation between the center of the substrate support plate and the center of the wear (the amount of deviation can be grasped as the overlap amount) is within a desired range. It is necessary to be.

  Conventionally, in order to measure the overlay amount, at least three or more distances from the edge of the substrate support plate to the edge of the wafer attached to the substrate support plate are measured (hereinafter, simply three or more points). This was called measurement), and it was confirmed whether or not the overlap amount was within a desired range.

  Note that Patent Documents 1, 2, and 3 exist as prior documents for attaching a wafer to a wafer holding plate in the polishing process of the wafer.

JP 2000-271864 A JP 2000-271863 A JP 2000-271862 A

  Conventionally, as described above, it is necessary to measure three or more points in the measurement of the overlay amount. However, the measurement of three or more points has difficulty in measurement, and it has been necessary to measure using a dedicated dimension measuring machine.

  Also, it is very difficult to control the amount of temporary adhesive protruding from the edge of the wafer. Therefore, in a portion where the distance from the edge of the wafer to the edge of the substrate support plate is short, the temporary adhesive protruding from the edge of the wafer is transferred from the side surface of the substrate support plate to the back surface of the substrate support plate (wafer non-bonded). (Hereinafter referred to as temporary adhesive wraparound). The wraparound of the temporary adhesive becomes a source of foreign matter and causes a decrease in product yield.

  Therefore, the present invention relates to a technique including a step of attaching a wafer to a substrate support plate during manufacture of the wafer, and can easily (simplely) measure the overlay amount, and further temporarily bond It is an object of the present invention to provide a substrate support plate and a method for temporarily fixing a wafer to the substrate support plate, which can prevent the agent from wrapping around.

  In order to achieve the above object, a substrate support plate according to the present invention includes a main surface to which a wafer is fixed, and an overlap formed on the main surface, which indicates an arrangement position limit of the wafer on the main surface. And an alignment limit mark.

  Further, the method of temporarily fixing a wafer to a substrate support plate according to the present invention includes (A) a step of preparing a substrate support plate having an overlay limit area mark formed on a main surface to which the wafer is fixed, and (B). A step of temporarily fixing the wafer to the main surface via a temporary adhesive; and (C) whether the wafer is fixed to the substrate support plate so as not to overlap the overlap limit area mark. And a step of observing success or failure.

  In the present invention, the substrate support plate includes a main surface to which a wafer is fixed, and an overlap limit area mark formed on the main surface that indicates a limit of the arrangement position of the wafer on the main surface. Then, it is observed whether or not the wafer is fixed to the substrate support plate so as not to overlap the overlap limit area mark.

  Therefore, it is possible to confirm whether or not the overlay amount is within a desired range (that is, the wafer is within a desired range on the substrate support plate) at a simple (simple) and low cost.

It is a top view which shows the structure of the board | substrate support board 1 which concerns on this invention. It is a top view which shows the other structural example of the board | substrate support board 1 which concerns on this invention. It is the enlarged plan view which expanded and displayed the partial structure of the board | substrate support board 1 which concerns on this invention. It is the expanded sectional view which expanded and displayed the partial composition of substrate support board 1 concerning the present invention. FIG. 6 is an enlarged cross-sectional view in which a configuration in the vicinity of an overlap limit area mark 2 is enlarged and displayed. FIG. 6 is an enlarged cross-sectional view in which another configuration example of the superposition limit area mark 2 is enlarged and displayed. It is sectional drawing for demonstrating the wafer temporary adhering method to the board | substrate support board 1 which concerns on this invention. It is sectional drawing which shows wafer temporary fixation to the board | substrate support board 1 which does not have the superposition limit area mark 2. FIG. It is sectional drawing which shows wafer temporary fixation to the board | substrate support board 1 which does not have the superposition limit area mark 2. FIG. FIG. 6 is a plan view showing an example of a temporary fixing mode of the substrate support plate 1 and the wafer 10 that is determined as “composition” as a result of checking the amount of overlap. FIG. 6 is a plan view showing an example of a temporary fixing mode of the substrate support plate 1 and the wafer 10 that is determined as “No” as a result of checking the overlapping amount.

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.

  FIG. 1 is a plan view showing a configuration of a substrate support plate 1 according to the present invention. A wafer such as a Si wafer or a SiC wafer is temporarily fixed to the main surface of the substrate support plate 1 (the surface appearing on the paper surface of FIG. 1). Specifically, a wafer is attached to the main surface of the substrate support plate 1 via a temporary adhesive. Here, the term “temporary” means that the wafer is temporarily attached (fixed) to the substrate support plate 1 during the manufacturing process, and after a predetermined process on the wafer, the wafer is removed from the substrate support plate 1. It is because it peels.

  In plan view, the wafer needs to be attached so that the wafer fits within the frame of the substrate support plate 1. This is because when the wafer protrudes outside the frame of the substrate support plate 1, the wafer is externally damaged at the protruding portion.

  For example, in the case of processing on a wafer with rotation, the center of the substrate support plate 1 to which the wafer is attached is used for the processing. Therefore, in order for the processing to be normally performed on the wafer, the distance between the center A of the substrate support plate 1 and the center of the bonded wafer (that is, the deviation between both centers) needs to be within a predetermined range. There is. In other words, it is necessary that the overlay amount described above is within a predetermined range.

  In view of this, on the main surface of the substrate support plate 1 according to the present invention, an overlap limit area mark (shaded portion in FIG. 1) 2 is formed, which indicates a wafer placement position limit on the main surface. The overlapping limit area mark 2 is a recess (groove) dug at a predetermined depth on the main surface of the substrate support plate 1.

  Here, the overlap limit area mark 2 formed on the substrate support plate 1 may be a simple planar mark other than the recess (groove). However, it is more preferable that the overlap limit area mark 2 formed on the substrate support plate 1 is the concave portion (groove). Further, as shown in FIG. 2, a plurality of overlapping limit area marks 2 may be discretely formed on the main surface of the substrate support plate 1. However, as shown in FIG. 1, in the vicinity of the outer peripheral portion of the main surface of the substrate support plate 1, it is more preferable that the overlap limit area mark 2 is continuously formed in an annular shape.

  The overlay limit area mark 2 indicates a wafer placement position limit on the main surface. Therefore, the overlap limit area mark 2 is formed on the main surface of the substrate support plate 1 in a range that allows the overlap amount.

  That is, if the wafer is attached to the substrate support plate 1 so that all the overlap limit area marks 2 can be desired in plan view, the wafer is overlapped on the substrate support plate 1. Is pasted within an allowable range. On the other hand, when the wafer is affixed to the substrate support plate 1 so that the overlap limit area mark 2 is partially covered by the wafer in plan view, the wafer is placed on the substrate support plate 1. In this state, when a predetermined process is performed on the wafer bonded to the substrate support plate 1, the process is normally performed. Not likely to be).

  The depth and width of the overlay limit area mark 2 are appropriately set according to the material and thickness of the temporary adhesive used.

  3 is an enlarged plan view of a region surrounded by a dotted line in FIG. 1, and FIG. 4 is an enlarged cross-sectional view showing a section XX ′ in FIG. FIG. 5 is an enlarged cross-sectional view in which the configuration in the vicinity of the overlap limit area mark 2 in FIG. 4 is further enlarged. Here, in FIG. 5, the left side of the drawing is the edge side of the substrate support plate 1, and the right side of the drawing is the center A side of the substrate support plate 1.

  As shown in FIGS. 4 and 5, the overlapping limit area mark 2 which is a concave portion has a tapered cross section. Specifically, the side surface close to the edge of the substrate support plate 1 inside the groove of the recess has an angle θ formed by the main surface of the substrate support plate 1 and the extension line L of the side surface of 90 degrees. It is formed so that a smaller taper angle is formed. That is, of the both side surfaces of the recess, at least the side surface close to the edge of the substrate support plate 1 is formed so as to be inclined so that the recess extends.

  In the configuration shown in FIGS. 4 and 5, the side surface near the center A of the substrate support plate 1 inside the groove of the recess is formed by the main surface of the substrate support plate 1 and an extension line of the side surface. The taper angle is smaller than 90 degrees. For example, the angle θ can be about 45 to 60 degrees.

  Here, as shown in FIG. 6, the overlap limit area mark 2 that is a recess may have a rectangular cross section that is not tapered (or the opening of the groove is narrower than the bottom of the groove, The cross-sectional shape may be a reverse taper). However, it is more preferable that the overlapping limit area mark 2 which is a concave portion has a tapered cross section.

  Next, a method for temporarily attaching a wafer to a substrate support plate according to the present invention will be described.

  First, a substrate support plate 1 made of, for example, disc-shaped silicon or glass is prepared. And a recessed part is formed in the predetermined part of the main surface of the said board | substrate support board 1, and the overlap limit area mark 2 is formed on the said main surface.

  Next, a temporary adhesive 5 is applied to the main surface of the substrate support plate 1 on which the overlapping limit area mark 2 is formed, and the wafer 10 is placed on the main surface via the temporary adhesive 5. Is temporarily bonded and fixed (see FIG. 7). Here, as shown in FIG. 7, the temporary adhesive 5 protruding from the edge of the wafer 10 flows into the concave overlapping limit area mark 2.

  Here, as shown in FIG. 8, the overlap limit mark 2 is not formed on the substrate support plate 1, and the wafer 10 is temporarily bonded and fixed on the substrate support plate 1 via the temporary adhesive 5. Suppose that As in the example of FIG. 8, in a portion where the distance from the edge of the wafer 10 to the edge of the substrate support plate 1 is long, the temporary adhesive 5 a that protrudes from the edge of the wafer 10 is applied to the end of the substrate support plate 1. Never reach the side. However, in a portion where the distance from the edge of the wafer 10 to the edge of the substrate support plate 1 is short, the temporary adhesive 5a protruding from the edge of the wafer 10 is transferred from the end side surface of the substrate support plate 1 to the substrate support plate. It reaches the back side (wafer non-bonding side). That is, the wraparound of the temporary adhesive described above occurs.

  On the other hand, the overlap limit mark 2 is formed on the substrate support plate 1 according to the present invention. Accordingly, the temporary adhesive 5 protruding from the edge of the wafer 10 flows into the concave overlapping limit area mark 2. Therefore, when the substrate support plate 1 according to the present invention is employed, the temporary adhesive 5 protruding from the edge of the wafer 10 can be prevented from reaching the edge of the substrate support plate 1, and FIG. 9 is used. As described above, the temporary adhesive does not wrap around.

  Now, after temporarily fixing the wafer 10 to the substrate support plate 1, the amount of overlap is measured, and it is confirmed whether or not the wafer 10 is temporarily fixed in a desired region in front of the substrate support plate 1. .

  Here, as shown in FIG. 8, the overlap limit mark 2 is not formed on the substrate support plate 1, and the wafer 10 is temporarily bonded and fixed on the substrate support plate 1 via the temporary adhesive 5. Suppose that In this case, as described in “Background Art”, the distance from the edge of the substrate support plate 1 to the edge of the wafer 10 affixed to the substrate support plate 1 in order to measure the overlay amount. D1 is measured at least 3 points (measured above 3 points), and it is confirmed whether or not the overlay amount is within a desired range (that is, the wafer 10 is within a desired range on the substrate support plate 1). It was. The measurement of three or more points is a very complicated operation and requires a dedicated dimension measuring machine, which is expensive.

  On the other hand, the overlap limit mark 2 is formed on the substrate support plate 1 according to the present invention. Therefore, by attaching the wafer 10 on the substrate support plate 1 and visually observing whether or not there is a portion where the overlap limit mark 2 is covered by the wafer 10, the wafer 10 is supported by the substrate. It can be determined whether or not it is temporarily fixed within a desired range on the plate 1. That is, by adopting the substrate support plate 1 according to the present invention, the overlay amount is within a desired range (that is, the wafer 10 is within a desired range on the substrate support plate 1) easily and at low cost. You can check whether or not.

  As described above, if the wafer 10 is affixed to the substrate support plate 1 so that all the overlap limit area marks 2 can be desired in plan view, the wafer 10 is placed on the substrate support plate 1 plate. In FIG. 4, the amount of overlap is pasted within an allowable range (determined as “successful” as a result of confirmation of the amount of overlap). On the other hand, if the wafer 10 is affixed to the substrate support plate 1 so that the overlap limit area mark 2 is partially covered by the wafer 10 in plan view, the wafer 10 1, the overlay amount is pasted beyond the allowable range (determined as “No” as a result of the overlay amount confirmation).

  FIG. 10 is a plan view showing an example of a temporary fixing mode between the substrate support plate 1 and the wafer 10 that is determined as “successful” as a result of confirmation of the overlay amount (that is, an annular overlay limit area mark). 2 is a plan view in the case where the wafer 10 is accommodated inside 2). FIG. 11 is a plan view showing an example of a temporary fixing mode of the substrate support plate 1 and the wafer 10 that is determined as “no” as a result of the overlay amount confirmation (that is, an annular overlay limit area mark). 2 is a plan view in the case where the wafer 10 is not accommodated inside 2). 10 and 11, the temporary adhesive 5 protruding from the edge of the wafer 10 is not shown for the sake of simplification.

  Here, even if the overlay limit area mark 2 is a mark formed on the substrate support plate 1 in a planar manner, whether or not the overlay amount confirmation is successful can be determined. However, in order to achieve the above-described effect of preventing the temporary adhesive from wrapping around, the overlap limit area mark 2 needs to be formed three-dimensionally (as a recess) on the substrate support plate 1.

  Now, when it is determined as “successful” as a result of the overlay amount confirmation, a desired process is performed on the wafer 10 fixed to the determined substrate support plate 1. After the desired processing, the wafer 10 is peeled from the substrate support plate 1. Specifically, while rotating the substrate support plate 1, the temporary adhesive 5 is dissolved using a predetermined solvent (organic solvent or the like), whereby the wafer 10 is peeled from the substrate support plate 1. Note that the wafer 10 may be peeled from the substrate support plate 1 by applying heat to the substrate support plate 1 and dissolving the temporary adhesive 5 without using a predetermined solvent.

  Here, as shown in FIG. 6, the cross-sectional shape of the overlap limit area mark 2 may be a rectangle (or the cross-sectional shape of the reverse taper). However, as shown in FIG. 5, when the substrate support plate 1 is rotated for the above-described peeling by making the cross-sectional shape of the overlap limit area mark 2 tapered, the temporary force caused by the rotation causes a temporary change. The solubility of the adhesive 5 is improved, and the used solvent and the temporary adhesive 5 can be completely removed from the inside of the overlapping limit area mark 2.

  As described above, in the substrate support plate 1 according to the present invention, the overlap limit area mark 2 is formed on the main surface to which the wafer 10 is fixed. Therefore, it is possible to confirm whether or not the overlapping amount is within a desired range (that is, within a desired range on the substrate support plate 1) at a simple (simple) and low cost.

  The overlap limit area mark 2 is a recess (groove) dug in the main surface of the substrate support plate 1. Therefore, the temporary adhesive 5 a that protrudes from the edge of the wafer 10 can be prevented from entering the concave portion and reaching the edge of the substrate support plate 1.

  As shown in FIG. 1, the overlap limit area mark 2 is a concave portion (groove) continuously dug in the main surface of the substrate support plate 1. Therefore, it is possible to prevent all the temporary adhesive 5 a protruding from the edge of the wafer 10 from entering the concave portion and reaching the edge of the substrate support plate 1. That is, the temporary adhesive 5a protruding from the edge of the wafer 10 can be prevented from leaking outside the annular overlap limit area mark 2, and as a result, the temporary adhesive can be prevented from wrapping around.

  Further, as shown in FIG. 5, the cross-sectional shape of the overlap limit area mark 2 is a tapered shape. Therefore, when the substrate support plate 1 is rotated to remove the wafer 10 and a solvent is used, the solubility of the temporary adhesive 5 is improved by the centrifugal force resulting from the rotation, and the solvent and the temporary adhesive used. 5 can be completely removed from the inside of the overlay limit area mark 2.

  The present invention can be applied, for example, in a manufacturing process of a wafer used in a power semiconductor device. Further, for example, the present invention can be applied in a manufacturing process of a wafer used in MEMS (Micro Electro Mechanical Systems).

  In addition, when this invention is employ | adopted, there exist effects, such as prevention of generation | occurrence | production of the said temporary adhesive agent, and a yield improves. Therefore, when a silicon carbide (SiC) wafer that is more expensive than a silicon wafer is employed as the wafer 10, the present invention works more effectively from the viewpoint of cost reduction.

  1 substrate support plate, 2 overlap limit mark, 5 temporary adhesive, 5a protruding temporary adhesive, 10 wafer, θ (taper) angle.

Claims (9)

A main surface to which the wafer is fixed;
A substrate support plate, comprising: an overlay limit area mark formed on the main surface, which indicates an arrangement position limit of the wafer on the main surface. The overlap limit mark is
It is a recess dug in the main surface,
The substrate support plate according to claim 1. The overlap limit mark is
In the main surface, the concave portion dug in an annular shape,
The board | substrate support board of Claim 2 characterized by the above-mentioned. Of the side surfaces of the recess, at least the side surface close to the edge of the substrate support plate is
It is formed so as to be inclined so that the concave portion is extended.
The substrate support plate according to claim 3. (A) preparing a substrate support plate having an overlap limit mark formed on the main surface to which the wafer is fixed;
(B) temporarily bonding the wafer to the main surface via a temporary adhesive;
(C) observing the success or failure of whether the wafer is fixed to the substrate support plate so as not to overlap with the overlay limit area mark,
A method for temporarily adhering a wafer to a substrate support plate. The overlap limit mark is
It is a recess dug in the main surface,
The method for temporarily fixing a wafer to a substrate support plate according to claim 5. The overlap limit mark is
In the main surface, the concave portion dug in an annular shape,
The method for temporarily adhering a wafer to a substrate support plate according to claim 6. Of the side surfaces of the recess, at least the side surface close to the edge of the substrate support plate is
It is formed so as to be inclined so that the concave portion is extended,
(D) performing a desired process on the wafer fixed to the substrate support plate, which is determined to be “successful” as a result of the observation in the step (C);
(E) After the step (D), further comprising the step of dissolving the temporary adhesive using a predetermined solvent while rotating the substrate support plate,
The method for temporarily fixing a wafer to a substrate support plate according to claim 7. The wafer is
A SiC wafer,
The method for temporarily fixing a wafer to a substrate support plate according to any one of claims 5 to 8.

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